A standardization work group in the 3rd Generation Partnership Project (3GPP) is currently working on revolution of Packet Switch (PS) Core and Universal Mobile Telecommunication System Radio Access Network (UTRAN). This research topic, also known as System Architecture Evolution (SAE), aims to allow an Evolved Packet Core (EPC) to provide a higher transmission rate and a low transmission delay, while optimizing packets and supporting mobility management among Evolved UTRAN (E-UTRAN), UTRAN, Wireless Local Area Network (WLAN) and other non-3GPP access networks.
FIG. 1 shows the current SAE architecture, including the following network element: an Evolved Radio Access Network (E-RAN), a packet data network and an Evolved Packet Core (E-Packet Core). The E-Packet Core includes the following network elements: a Mobility Management Entity (MME), a Serving Gateway (SGW), a Packet Data Network Gateway (PGW), a Policy and Charging Rules Function (PCRF) entity, a Home Subscriber Server (HSS) and a Service Capability Exposure Function (SCEF) entity.
When a User Equipment (UE) has a small data to be transmitted in the uplink, there is conventionally no procedure for the MME to trigger establishment of a non-Internet Protocol (IP) transmission channel. Hence, upon receiving an uplink non-IP data transmitted from the UE, the MME can either buffer it locally or discard it. When a Service Capability Server (SCS)/Application Server (AS) triggers establishment of a non-IP transmission channel, the MME can transmit the buffered uplink non-IP data to the SCS/AS. This requires additional storage at the MME and increases the MME's burden.
There is currently no solution to the above problem.